Organic charge transfer complexes (CPXs) on graphene with ultrahigh near infrared (NIR) photogain.

Photodetectors have widespread applications in telecommunication, thermal imaging, bio-medical imaging and so on. Photogating effect, arising from charge trapping at defects and/or interfaces, can have extremely high photoelectric gain, which can benefit to high-sensitivity room temperature photodetection. Here, we introduce thin layered organic CPXs integrated on graphene transistors for the development of hybrid phototransistors with ultra-high photoresponsivity of ~106 A/W in near infrared (NIR) region at room temperature. Our study has demonstrated graphene-organic CPX with a broadband photoresponse ranging from the visible to NIR region. The high photoelectric gain was from the photogating effect at the graphene/CPX interface. In addition, the photoresponse property of graphene-organic CPX can be regulated by electrical gating of graphene.